Red Dead Redemption 2 is a landmark technical achievement – and the end result of a unique development situation. With Grand Theft Auto 5, Rockstar has already developed the top-grossing title in the history of the games industry – and with that comes the confidence to invest all of the time, money and resources required to realise its vision for the ultimate game. The final product is technological masterpiece, matching and arguably exceeding the very best first-party efforts of this generation.

And that’s another key point that makes Red Dead Redemption 2 so fascinating. Grand Theft Auto 5 on PC, PS4 and Xbox One features myriad improvements over the original PS3/Xbox 360 releases, but fundamentally they are still titles with last-gen roots. Rockstar’s new game is obviously built with the current-generation platforms in mind, sharing with and building on many of the technical advances seen across the industry in recent years. That said, it’s also a game that feels decidedly different from other open world titles released this generation – almost as if it were built in isolation, and the team has focused on visual flourishes that you might not expect to see in such a game.

In essence then, what we’re looking at is a newly evolved iteration of Rockstar’s RAGE engine. There are many familiar elements here, but the developer has taken this opportunity to push its technical and presentation skills to a new level. And what’s equally impressive is that the studio has managed to deliver this at full native 4K on Xbox One X – but resolution is only one aspect of image quality. For starters, a proper temporal anti-aliasing has been implemented – with the long draw distances and lots of gritty detail on display, this is a must when it comes to reducing shimmering and giving a more temporally stable, filmic image. The TAA solution here is aggressive and does result in a softer overall look but the results are more cohesive, with everything from open fields of grass to fine texture detail and even beards blending nicely into the overall presentation.

Red Dead 2 also features per-object motion blur for perhaps the first time in Rockstar history – it’s a subtle effect but one that increases the sense of fluidity lacking in other open world games such as Assassin’s Creed Odyssey and The Witcher 3. But these are just basics aspects of image quality – the lens through which the game is viewed – and it’s the world itself that is this game’s defining achievement.

In building any open world, a development team faces many challenges when it comes to creating something that is both visually attractive and highly playable. From our perspective, the best open worlds offer a mix between a large sense of scale with vast swathes of terrain stretching out into the distance combined with a high volume of granular, close-range detail and a rich simulation. A world such as this is composed of many pieces – open terrain, dense forests, packed cities, tall mountains and vast skies.

Rockstar has actually spent a lot of time – and presumably GPU resources – in creating Red Dead Redemption 2’s immense skies, which play a huge part in building atmosphere and defining the landscape. In the past few years, developers have made advances in sky rendering, moving away from flat billboards and textures and developing more volumetric solutions. Red Dead 2’s cloud rendering system supports full time of day changes plus variable weather and cloud types, with sunlight realistically penetrating and scattering through the soft cloud bodies. When it rains or snows, light penetration is suitably reduced, simulating darker, thicker clouds that occur alongside inclement weather. In the right conditions, even rainbows can manifest across the environment.

With little information available on how this system has been implemented, however, we can only hypothesise how this was achieved. Based on our observations, we’re looking at a solution much like Horizon Zero Dawn, which basically involves ray marching through variable 2D and 3D noise textures. Guerrilla Games keeps the rendering cost low by updating clouds every 16 frames and reconstructing from this data and it seems like that a similar method is employed here. Clouds crawl smoothly across the sky in this game with minimal artefacts, even when simply observing their movement in real-time. There’s a greater variation to possible cloud formations as well, lending the game a greater sense of variety across its vast skies. What I really like most about Rockstar’s implementation, however, is how incoming storms are handled – the sky gradually darkens as the wind simulation becomes stronger while the surface below exhibits an eerie glow. It’s a remarkably evocative look.

It’s a remarkable leap over Grand Theft Auto 5, where the clouds are derived from a Perlin noise pattern mapped over a large dome which encircles the game world. This enables wide variation in cloud patterns, but it lacks the three-dimensionality you get with the volumetric system in Red Dead 2 – the clouds simply move along the surface of the virtual dome. It works just fine in real-time and its limitations are only really exposed in time-lapse, but Red Dead 2’s implementation is our first example of a true generational leap in the open world’s make-up. And this is just the beginning.

Light from the sky naturally casts shadows and these are of a quality rarely seen in a console open world game. Similar to GTA5, cascaded shadow maps appear to be utilised, but Rockstar has developed a clever new solution to simulate contact hardening. It’s a remarkable, computationally expensive way to create a more accurate effect, with shadows near the object presenting more sharply, gradually becoming more diffuse the further away they are. It’s all tied into the position of the sun and the length of the shadows – and being an open world title with a full time of day cycle, everything is generated dynamically in real-time. Not only that, but shadow rendering is also impacted by cloud cover too.